Single cell analysis of senile atopic dermatitis in Korean population

Summary: Abstract Body: Atopic Dermatitis (AD) is a chronic inflammatory skin disease accompanied by pruritus. It is classified into infancy, childhood, adolescence (including adulthood), and old age, each presenting distinct pathological characteristics. While most studies to date have focused on populations up to adulthood, the growing elderly population underscores the need for research on senile AD. AD is generally considered a Th2-skewed disease. However, in Asian populations, a pronounced shift toward the Th17 axis has been observed compared to Caucasians, and there are reports of strong Th17 signatures at the serum level in senile AD patients. Building on these previous findings, we performed single-cell RNA sequencing (scRNA-seq) on blood and pathological tissue samples from a Korean cohort of senile AD patients. Specifically, we collected skin punch biopsy samples from nine AD patients (including lesional and non-lesional sites) and six healthy controls, and additionally obtained a total of 15 blood samples from both patients and controls to characterize the unique immunological profile of senile AD. Through single-cell analysis of these samples, we identified 15,064 skin-derived cells, and plan to comprehensively evaluate the immune environment of senile AD by comparing these data with our in-house inflammatory skin disease atlas. Through this approach, we aim to determine whether a distinct immune axis exists in senile AD that diverges from the conventional Th2-dominated axis of AD. Furthermore, we seek to elucidate the unique changes observed in keratinocytes and fibroblasts, as well as their immunological interactions in senile AD. Ultimately, this study will provide deeper insights into the age-related immunological dynamics of AD and contribute to the development of tailored diagnostic and therapeutic strategies for senile AD. Hyunsung Nam¹, Hyun Jun Rha², Una Choi⁴, Youngkyoung Lim³, Hyun Je Kim^{1, 2} 1. College of Medicine, Seoul National University, Genomic Medicine Institute, Seoul, Korea (the Republic of). 2. Seoul National University College of Medicine, Jongno-gu, Seoul, Korea (the Republic of). 3. Dermatology, Veteran Health Service Medical Center, Seoul, Korea (the Republic of). 4. Inha University, Incheon, Korea (the Republic of). Bioinformatics, Computational Biology, and Imaging